C语言使用ffmpeg实现单线程异步的视频播放器
CodeOfCC 人气:0前言
ffplay是一个不错的播放器，是基于多线程实现的，播放视频时一般至少有4个线程：读包线程、视频解码线程、音频解码线程、视频渲染线程。如果需要多路播放时，线程不可避免的有点多，比如需要播放8路视频时则需要32个线程，这样对性能的消耗还是比较大的。于是想到用单线程实现一个播放器，经过实践发现是可行的，播放本地文件时可以做到完全单线程、播放网络流时需要一个线程实现读包异步。
一、播放流程
二、关键实现
因为是基于单线程的播放器有些细节还是要注意的。
1.视频
（1）解码
解码时需要注意设置多线程解码或者硬解以确保解码速度，因为在单线程中解码过慢则会导致视频卡顿。
//使用多线程解码
if (!av_dict_get(opts, "threads", NULL, 0))
av_dict_set(&opts, "threads", "auto", 0);
//打开解码器
if (avcodec_open2(decoder->codecContext, codec, &opts) < 0) {
LOG_ERROR("Could not open codec");
av_dict_free(&opts);
return ERRORCODE_DECODER_OPENFAILED;
}
或者根据情况设置硬解码器
codec = avcodec_find_decoder_by_name("hevc_qsv");
//打开解码器
if (avcodec_open2(decoder->codecContext, codec, &opts) < 0) {
LOG_ERROR("Could not open codec");
av_dict_free(&opts);
return ERRORCODE_DECODER_OPENFAILED;
}
2、音频
（1）修正时钟
虽然音频的播放是基于流的，时钟也可以按照播放的数据量计算，但是出现丢包或者定位的一些情况时，按照数据量累计的方式会导致时钟不正确，所以在解码后的数据放入播放队列时应该进行时钟修正。
synchronize_setClockTime参考《c语言 将音视频时钟同步封装成通用模块》。在音频解码之后：
//读取解码的音频帧 av_fifo_generic_read(play->audio.decoder.fifoFrame, &frame, sizeof(AVFrame*), NULL); //同步(修正)时钟 AVRational timebase = play->formatContext->streams[audio->decoder.streamIndex]->time_base; //当前帧的时间戳 double pts = (double)frame->pts * timebase.num / timebase.den; //减去播放队列剩余数据的时长就是当前的音频时钟 pts -= (double)av_audio_fifo_size(play->audio.playFifo) / play->audio.spec.freq; synchronize_setClockTime(&play->synchronize, &play->synchronize.audio, pts); //同步(修正)时钟--end //写入播放队列 av_audio_fifo_write(play->audio.playFifo, (void**)&data, samples);
3、时钟同步
需要时钟同步的地方有3处，一处是音频解码后即上面的2、（1）。另外两处则是音频播放和视频渲染的地方。
（1）音频播放
synchronize_updateAudio参考《c语言 将音视频时钟同步封装成通用模块》。
//sdl音频回调
static void audio_callback(void* userdata, uint8_t* stream, int len) {
Play* play = (Play*)userdata;
//需要写入的数据量
samples = play->audio.spec.samples;
//时钟同步，获取应该写入的数据量，如果是同步到音频，则需要写入的数据量始终等于应该写入的数据量。
samples = synchronize_updateAudio(&play->synchronize, samples, play->audio.spec.freq);
//略
}
（2）视频播放
在视频渲染处实现如下代码，其中synchronize_updateVideo参考《c语言 将音视频时钟同步封装成通用模块》。
//---------------时钟同步--------------
AVRational timebase = play->formatContext->streams[video->decoder.streamIndex]->time_base;
//计算视频帧的pts
double pts = frame->pts * (double)timebase.num / timebase.den;
//视频帧的持续时间
double duration = frame->pkt_duration * (double)timebase.num / timebase.den;
double delay = synchronize_updateVideo(&play->synchronize, pts, duration);
if (delay > 0)
//延时
{
play->wakeupTime = getCurrentTime() + delay;
return 0;
}
else if (delay < 0)
//丢帧
{
av_fifo_generic_read(video->decoder.fifoFrame, &frame, sizeof(AVFrame*), NULL);
av_frame_unref(frame);
av_frame_free(&frame);
return 0;
}
else
//播放
{
av_fifo_generic_read(video->decoder.fifoFrame, &frame, sizeof(AVFrame*), NULL);
}
//---------------时钟同步-------------- end4、异步读包
如果是本地文件单线程播放是完全没有问题的。但是播放网络流时，由于av_read_frame不是异步的，网络状况差时会导致延时过高影响到其他部分功能的正常进行，所以只能是将读包的操作放到子线程执行，这里采用async、await的思想实现异步。
（1）async
将av_read_frame的放到线程池中执行。
//异步读取包，子线程中调用此方法
static int packet_readAsync(void* arg)
{
Play* play = (Play*)arg;
play->eofPacket = av_read_frame(play->formatContext, &play->packet);
//回到播放线程处理包
play_beginInvoke(play, packet_readAwait, play);
return 0;
}
（2）await
执行完成后通过消息队列通知播放器线程，将后续操作放在播放线程中执行
//异步读取包完成后的操作
static int packet_readAwait(void* arg)
{
Play* play = (Play*)arg;
if (play->eofPacket == 0)
{
if (play->packet.stream_index == play->video.decoder.streamIndex)
//写入视频包队
{
AVPacket* packet = av_packet_clone(&play->packet);
av_fifo_generic_write(play->video.decoder.fifoPacket, &packet, sizeof(AVPacket*), NULL);
}
else if (play->packet.stream_index == play->audio.decoder.streamIndex)
//写入音频包队
{
AVPacket* packet = av_packet_clone(&play->packet);
av_fifo_generic_write(play->audio.decoder.fifoPacket, &packet, sizeof(AVPacket*), NULL);
}
av_packet_unref(&play->packet);
}
else if (play->eofPacket == AVERROR_EOF)
{
play->eofPacket = 1;
//写入空包flush解码器中的缓存
AVPacket* packet = &play->packet;
if (play->audio.decoder.fifoPacket)
av_fifo_generic_write(play->audio.decoder.fifoPacket, &packet, sizeof(AVPacket*), NULL);
if (play->video.decoder.fifoPacket)
av_fifo_generic_write(play->video.decoder.fifoPacket, &packet, sizeof(AVPacket*), NULL);
}
else
{
LOG_ERROR("read packet erro!\n");
play->exitFlag = 1;
play->isAsyncReading = 0;
return ERRORCODE_PACKET_READFRAMEFAILED;
}
play->isAsyncReading = 0;
return 0;
}
（3）消息处理
在播放线程中调用如下方法，处理事件，当await方法抛入消息队列后，就可以通过消息循环获取await方法在播放线程中执行。
//事件处理
static void play_eventHandler(Play* play) {
PlayMessage msg;
while (messageQueue_poll(&play->mq, &msg)) {
switch (msg.type)
{
case PLAYMESSAGETYPE_INVOKE:
SDL_ThreadFunction fn = (SDL_ThreadFunction)msg.param1;
fn(msg.param2);
break;
}
}
}
三、完整代码
完整代码c和c++都可以运行，使用ffmpeg4.3、sdl2。
main.c/cpp
#include <stdio.h>
#include <stdint.h>
#include "SDL.h"
#include<stdint.h>
#include<string.h>
#ifdef __cplusplus
extern "C" {
#endif
#include "libavformat/avformat.h"
#include "libavcodec/avcodec.h"
#include "libswscale/swscale.h"
#include "libavutil/imgutils.h"
#include "libavutil/avutil.h"
#include "libavutil/time.h"
#include "libavutil/audio_fifo.h"
#include "libswresample/swresample.h"
#ifdef __cplusplus
}
#endif
/************************************************************************
* @Project: play
* @Decription: 视频播放器
* 这是一个播放器，基于单线程实现的播放器。如果是播放本地文件可以做到完全单线程，播放网络流则读取包的时候是异步的，当然
* 主流程依然是单线程。目前是读取包始终异步，未作判断本地文件同步读包处理。
* @Verision: v0.0.0
* @Author: Xin Nie
* @Create: 2022/12/12 21:21:00
* @LastUpdate: 2022/12/12 21:21:00
************************************************************************
* Copyright @ 2022. All rights reserved.
************************************************************************/
/// <summary>
/// 消息队列
/// </summary>
typedef struct {
//队列长度
int _capacity;
//消息对象大小
int _elementSize;
//队列
AVFifoBuffer* _queue;
//互斥变量
SDL_mutex* _mtx;
//条件变量
SDL_cond* _cv;
}MessageQueue;
/// <summary>
/// 对象池
/// </summary>
typedef struct {
//对象缓存
void* buffer;
//对象大小
int elementSize;
//对象个数
int arraySize;
//对象使用状态1使用，0未使用
int* _arrayUseState;
//互斥变量
SDL_mutex* _mtx;
//条件变量
SDL_cond* _cv;
}OjectPool;
/// <summary>
/// 线程池
/// </summary>
typedef struct {
//最大线程数
int maxThreadCount;
//线程信息对象池
OjectPool _pool;
}ThreadPool;
/// <summary>
/// 线程信息
/// </summary>
typedef struct {
//所属线程池
ThreadPool* _threadPool;
//线程句柄
SDL_Thread* _thread;
//消息队列
MessageQueue _queue;
//线程回调方法
SDL_ThreadFunction _fn;
//线程回调参数
void* _arg;
}ThreadInfo;
//解码器
typedef struct {
//解码上下文
AVCodecContext* codecContext;
//解码器
const AVCodec* codec;
//解码临时帧
AVFrame* frame;
//包队列
AVFifoBuffer* fifoPacket;
//帧队列
AVFifoBuffer* fifoFrame;
//流下标
int streamIndex;
//解码结束标记
int eofFrame;
}Decoder;
/// <summary>
/// 时钟对象
/// </summary>
typedef struct {
//起始时间
double startTime;
//当前pts
double currentPts;
}Clock;
/// <summary>
/// 时钟同步类型
/// </summary>
typedef enum {
//同步到音频
SYNCHRONIZETYPE_AUDIO,
//同步到视频
SYNCHRONIZETYPE_VIDEO,
//同步到绝对时钟
SYNCHRONIZETYPE_ABSOLUTE
}SynchronizeType;
/// <summary>
/// 时钟同步对象
/// </summary>
typedef struct {
/// <summary>
/// 音频时钟
/// </summary>
Clock audio;
/// <summary>
/// 视频时钟
/// </summary>
Clock video;
/// <summary>
/// 绝对时钟
/// </summary>
Clock absolute;
/// <summary>
/// 时钟同步类型
/// </summary>
SynchronizeType type;
/// <summary>
/// 估算的视频帧时长
/// </summary>
double estimateVideoDuration;
/// <summary>
/// 估算视频帧数
/// </summary>
double n;
}Synchronize;
//视频模块
typedef struct {
//解码器
Decoder decoder;
//输出格式
enum AVPixelFormat forcePixelFormat;
//重采样对象
struct SwsContext* swsContext;
//重采样缓存
uint8_t* swsBuffer;
//渲染器
SDL_Renderer* sdlRenderer;
//纹理
SDL_Texture* sdlTexture;
//窗口
SDL_Window* screen;
//窗口宽
int screen_w;
//窗口高
int screen_h;
//旋转角度
double angle;
//播放结束标记
int eofDisplay;
//播放开始标记
int sofDisplay;
}Video;
//音频模块
typedef struct {
//解码器
Decoder decoder;
//输出格式
enum AVSampleFormat forceSampleFormat;
//音频设备id
SDL_AudioDeviceID audioId;
//期望的音频设备参数
SDL_AudioSpec wantedSpec;
//实际的音频设备参数
SDL_AudioSpec spec;
//重采样对象
struct SwrContext* swrContext;
//重采样缓存
uint8_t* swrBuffer;
//播放队列
AVAudioFifo* playFifo;
//播放队列互斥锁
SDL_mutex* mutex;
//累积的待播放采样数
int accumulateSamples;
//音量
int volume;
//声音混合buffer
uint8_t* mixBuffer;
//播放结束标记
int eofPlay;
//播放开始标记
int sofPlay;
}Audio;
//播放器
typedef struct {
//视频url
char* url;
//解复用上下文
AVFormatContext* formatContext;
//包
AVPacket packet;
//是否正在读取包
int isAsyncReading;
//包读取结束标记
int eofPacket;
//视频模块
Video video;
//音频模块
Audio audio;
//时钟同步
Synchronize synchronize;
//延时结束时间
double wakeupTime;
//播放一帧
int step;
//是否暂停
int isPaused;
//是否循环
int isLoop;
//退出标记
int exitFlag;
//消息队列
MessageQueue mq;
}Play;
//播放消息类型
typedef enum {
//调用方法
PLAYMESSAGETYPE_INVOKE
}PlayMessageType;
//播放消息
typedef struct {
PlayMessageType type;
void* param1;
void* param2;
}PlayMessage;
//格式映射
static const struct TextureFormatEntry {
enum AVPixelFormat format;
int texture_fmt;
} sdl_texture_format_map[] = {
{ AV_PIX_FMT_RGB8, SDL_PIXELFORMAT_RGB332 },
{ AV_PIX_FMT_RGB444, SDL_PIXELFORMAT_RGB444 },
{ AV_PIX_FMT_RGB555, SDL_PIXELFORMAT_RGB555 },
{ AV_PIX_FMT_BGR555, SDL_PIXELFORMAT_BGR555 },
{ AV_PIX_FMT_RGB565, SDL_PIXELFORMAT_RGB565 },
{ AV_PIX_FMT_BGR565, SDL_PIXELFORMAT_BGR565 },
{ AV_PIX_FMT_RGB24, SDL_PIXELFORMAT_RGB24 },
{ AV_PIX_FMT_BGR24, SDL_PIXELFORMAT_BGR24 },
{ AV_PIX_FMT_0RGB32, SDL_PIXELFORMAT_RGB888 },
{ AV_PIX_FMT_0BGR32, SDL_PIXELFORMAT_BGR888 },
{ AV_PIX_FMT_NE(RGB0, 0BGR), SDL_PIXELFORMAT_RGBX8888 },
{ AV_PIX_FMT_NE(BGR0, 0RGB), SDL_PIXELFORMAT_BGRX8888 },
{ AV_PIX_FMT_RGB32, SDL_PIXELFORMAT_ARGB8888 },
{ AV_PIX_FMT_RGB32_1, SDL_PIXELFORMAT_RGBA8888 },
{ AV_PIX_FMT_BGR32, SDL_PIXELFORMAT_ABGR8888 },
{ AV_PIX_FMT_BGR32_1, SDL_PIXELFORMAT_BGRA8888 },
{ AV_PIX_FMT_YUV420P, SDL_PIXELFORMAT_IYUV },
{ AV_PIX_FMT_YUYV422, SDL_PIXELFORMAT_YUY2 },
{ AV_PIX_FMT_UYVY422, SDL_PIXELFORMAT_UYVY },
{ AV_PIX_FMT_NONE, SDL_PIXELFORMAT_UNKNOWN },
};
/// <summary>
/// 错误码
/// </summary>
typedef enum {
//无错误
ERRORCODE_NONE = 0,
//播放
ERRORCODE_PLAY_OPENINPUTSTREAMFAILED = -0xffff,//打开输入流失败
ERRORCODE_PLAY_VIDEOINITFAILED,//视频初始化失败
ERRORCODE_PLAY_AUDIOINITFAILED,//音频初始化失败
ERRORCODE_PLAY_LOOPERROR,//播放循环错误
ERRORCODE_PLAY_READPACKETERROR,//解包错误
ERRORCODE_PLAY_VIDEODECODEERROR,//视频解码错误
ERRORCODE_PLAY_AUDIODECODEERROR,//音频解码错误
ERRORCODE_PLAY_VIDEODISPLAYERROR,//视频播放错误
ERRORCODE_PLAY_AUDIOPLAYERROR,//音频播放错误
//解包
ERRORCODE_PACKET_CANNOTOPENINPUTSTREAM,//无法代码输入流
ERRORCODE_PACKET_CANNOTFINDSTREAMINFO,//查找不到流信息
ERRORCODE_PACKET_DIDNOTFINDDANYSTREAM,//找不到任何流
ERRORCODE_PACKET_READFRAMEFAILED,//读取包失败
//解码
ERRORCODE_DECODER_CANNOTALLOCATECONTEXT,//解码器上下文申请内存失败
ERRORCODE_DECODER_SETPARAMFAILED,//解码器上下文设置参数失败
ERRORCODE_DECODER_CANNOTFINDDECODER,//找不到解码器
ERRORCODE_DECODER_OPENFAILED,//打开解码器失败
ERRORCODE_DECODER_SENDPACKEDFAILED,//解码失败
ERRORCODE_DECODER_MISSINGASTREAMTODECODE,//缺少用于解码的流
//视频
ERRORCODE_VIDEO_DECODERINITFAILED,//音频解码器初始化失败
ERRORCODE_VIDEO_CANNOTGETSWSCONTEX,//无法获取ffmpeg swsContext
ERRORCODE_VIDEO_IMAGEFILLARRAYFAILED,//将图像数据映射到数组时失败：av_image_fill_arrays
ERRORCODE_VIDEO_CANNOTRESAMPLEAFRAME,//无法重采样视频帧
ERRORCODE_VIDEO_MISSINGSTREAM,//缺少视频流
//音频
ERRORCODE_AUDIO_DECODERINITFAILED,//音频解码器初始化失败
ERRORCODE_AUDIO_UNSUPORTDEVICESAMPLEFORMAT,//不支持音频设备采样格式
ERRORCODE_AUDIO_SAMPLESSIZEINVALID,//采样大小不合法
ERRORCODE_AUDIO_MISSINGSTREAM,//缺少音频流
ERRORCODE_AUDIO_SWRINITFAILED,//ffmpeg swr重采样对象初始化失败
ERRORCODE_AUDIO_CANNOTCONVERSAMPLE,//音频重采样失败
ERRORCODE_AUDIO_QUEUEISEMPTY,//队列数据为空
//帧
ERRORCODE_FRAME_ALLOCFAILED,//初始化帧失败
//队列
ERRORCODE_FIFO_ALLOCFAILED,//初始化队列失败
//sdl
ERRORCODE_SDL_INITFAILED,//sdl初始化失败
ERRORCODE_SDL_CANNOTCREATEMUTEX,//无法创建互斥锁
ERRORCODE_SDL_CANNOTOPENDEVICE, //无法打开音频设备
ERRORCODE_SDL_CREATEWINDOWFAILED,//创建窗口失败
ERRORCODE_SDL_CREATERENDERERFAILED,//创建渲染器失败
ERRORCODE_SDL_CREATETEXTUREFAILED,//创建纹理失败
//内存
ERRORCODE_MEMORY_ALLOCFAILED,//申请内存失败
ERRORCODE_MEMORY_LEAK,//内存泄漏
//参数
ERRORCODE_ARGUMENT_INVALID,//参数不合法
ERRORCODE_ARGUMENT_OUTOFRANGE,//超出范围
}ErrorCode;
/// <summary>
/// 日志等级
/// </summary>
typedef enum {
LOGLEVEL_NONE = 0,
LOGLEVEL_INFO = 1,
LOGLEVEL_DEBUG = 2,
LOGLEVEL_TRACE = 4,
LOGLEVEL_WARNNING = 8,
LOGLEVEL_ERROR = 16,
LOGLEVEL_ALL = LOGLEVEL_INFO | LOGLEVEL_DEBUG | LOGLEVEL_TRACE | LOGLEVEL_WARNNING | LOGLEVEL_ERROR
}
LogLevel;
//输出日志
#define LOGHELPERINTERNALLOG(message,level,...) aclog(__FILE__,__FUNCTION__,__LINE__,level,message,##__VA_ARGS__)
#define LOG_INFO(message,...) LOGHELPERINTERNALLOG(message,LOGLEVEL_INFO, ##__VA_ARGS__)
#define LOG_DEBUG(message,...) LOGHELPERINTERNALLOG(message,LOGLEVEL_DEBUG,##__VA_ARGS__)
#define LOG_TRACE(message,...) LOGHELPERINTERNALLOG(cmessage,LOGLEVEL_TRACE,##__VA_ARGS__)
#define LOG_WARNNING(message,...) LOGHELPERINTERNALLOG(message,LOGLEVEL_WARNNING,##__VA_ARGS__)
#define LOG_ERROR(message,...) LOGHELPERINTERNALLOG(message,LOGLEVEL_ERROR,##__VA_ARGS__)
static int logLevelFilter = LOGLEVEL_ALL;
static ThreadPool* _pool = NULL;
//写日志
void aclog(const char* fileName, const char* methodName, int line, LogLevel level, const char* message, ...) {
if ((logLevelFilter & level) == 0)
return;
char dateTime[32];
time_t tt = time(0);
struct tm* t;
va_list valist;
char buf[512];
char* pBuf = buf;
va_start(valist, message);
int size = vsnprintf(pBuf, sizeof(buf), message, valist);
if (size > sizeof(buf))
{
pBuf = (char*)av_malloc(size + 1);
vsnprintf(pBuf, size + 1, message, valist);
}
va_end(valist);
t = localtime(&tt);
sprintf(dateTime, "%04d-%02d-%02d %02d:%02d:%02d", t->tm_year + 1900, t->tm_mon + 1, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec);
//在此处可替换为写文件
printf("%s %d %d %s %s %d: %s\n", dateTime, level, SDL_ThreadID(), fileName, methodName, line, pBuf);
if (pBuf != buf)
av_free(pBuf);
}
//日志过滤，设为LOGLEVEL_NONE则不输出日志
void setLogFilter(LogLevel level) {
logLevelFilter = level;
}
//初始化消息队列
int messageQueue_init(MessageQueue* _this, int capacity, int elementSize) {
_this->_queue = av_fifo_alloc(elementSize * capacity);
if (!_this->_queue)
return ERRORCODE_MEMORY_ALLOCFAILED;
_this->_mtx = SDL_CreateMutex();
if (!_this->_mtx)
return ERRORCODE_MEMORY_ALLOCFAILED;
_this->_cv = SDL_CreateCond();
if (!_this->_cv)
return ERRORCODE_MEMORY_ALLOCFAILED;
_this->_capacity = capacity;
_this->_elementSize = elementSize;
return 0;
}
//反初始化消息队列
void messageQueue_deinit(MessageQueue* _this) {
if (_this->_queue)
av_fifo_free(_this->_queue);
if (_this->_cv)
SDL_DestroyCond(_this->_cv);
if (_this->_mtx)
SDL_DestroyMutex(_this->_mtx);
memset(_this, 0, sizeof(MessageQueue));
}
//推入消息
int messageQueue_push(MessageQueue* _this, void* msg) {
int ret = 0;
SDL_LockMutex(_this->_mtx);
ret = av_fifo_generic_write(_this->_queue, msg, _this->_elementSize, NULL);
SDL_CondSignal(_this->_cv);
SDL_UnlockMutex(_this->_mtx);
return ret > 0;
}
//轮询序消息
int messageQueue_poll(MessageQueue* _this, void* msg) {
SDL_LockMutex(_this->_mtx);
int size = av_fifo_size(_this->_queue);
if (size >= _this->_elementSize)
{
av_fifo_generic_read(_this->_queue, msg, _this->_elementSize, NULL);
}
SDL_UnlockMutex(_this->_mtx);
return size;
}
//等待消息
void messageQueue_wait(MessageQueue* _this, void* msg) {
SDL_LockMutex(_this->_mtx);
while (1) {
int size = av_fifo_size(_this->_queue);
if (size >= _this->_elementSize)
{
av_fifo_generic_read(_this->_queue, msg, _this->_elementSize, NULL);
break;
}
SDL_CondWait(_this->_cv, _this->_mtx);
}
SDL_UnlockMutex(_this->_mtx);
}
//初始化对象池
int ojectPool_init(OjectPool* _this, void* bufferArray, int elementSize, int arraySize)
{
if (elementSize < 1 || arraySize < 1)
return ERRORCODE_ARGUMENT_INVALID;
_this->buffer = (unsigned char*)bufferArray;
_this->elementSize = elementSize;
_this->arraySize = arraySize;
_this->_arrayUseState = (int*)av_mallocz(sizeof(int) * arraySize);
if (!_this->_arrayUseState)
return ERRORCODE_MEMORY_ALLOCFAILED;
_this->_mtx = SDL_CreateMutex();
if (!_this->_mtx)
return ERRORCODE_MEMORY_ALLOCFAILED;
_this->_cv = SDL_CreateCond();
if (!_this->_cv)
return ERRORCODE_MEMORY_ALLOCFAILED;
return 0;
}
//反初始化对象池
void objectPool_deinit(OjectPool* _this)
{
av_free(_this->_arrayUseState);
if (_this->_cv)
SDL_DestroyCond(_this->_cv);
if (_this->_mtx)
SDL_DestroyMutex(_this->_mtx);
memset(_this, 0, sizeof(OjectPool));
}
//取出对象
void* objectPool_take(OjectPool* _this, int timeout) {
void* element = NULL;
SDL_LockMutex(_this->_mtx);
while (1)
{
for (int i = 0; i < _this->arraySize; i++)
{
if (!_this->_arrayUseState[i])
{
element = &((Uint8*)_this->buffer)[i * _this->elementSize];
_this->_arrayUseState[i] = 1;
break;
}
}
if (!element)
{
if (timeout == -1)
{
int ret = SDL_CondWait(_this->_cv, _this->_mtx);
if (ret == -1)
{
LOG_ERROR("SDL_CondWait error");
break;
}
}
else
{
int ret = SDL_CondWaitTimeout(_this->_cv, _this->_mtx, timeout);
if (ret != 0)
{
if (ret == -1)
{
LOG_ERROR("SDL_CondWait error");
}
break;
}
}
}
else
{
break;
}
}
SDL_UnlockMutex(_this->_mtx);
return element;
}
//归还对象
void objectPool_restore(OjectPool* _this, void* element) {
SDL_LockMutex(_this->_mtx);
for (int i = 0; i < _this->arraySize; i++)
{
if (_this->_arrayUseState[i] && &((Uint8*)_this->buffer)[i * _this->elementSize] == element)
{
SDL_CondSignal(_this->_cv);
_this->_arrayUseState[i] = 0;
break;
}
}
SDL_UnlockMutex(_this->_mtx);
}
//初始化线程池
int threadPool_init(ThreadPool* _this, int maxThreadCount) {
_this->maxThreadCount = maxThreadCount;
return ojectPool_init(&_this->_pool, av_mallocz(sizeof(ThreadInfo) * maxThreadCount), sizeof(ThreadInfo), maxThreadCount);
}
//反初始化线程池
void threadPool_denit(ThreadPool* _this) {
ThreadInfo* threads = (ThreadInfo*)_this->_pool.buffer;
if (threads)
{
for (int i = 0; i < _this->maxThreadCount; i++)
{
int status;
if (threads[i]._thread)
{
int msg = 0;
messageQueue_push(&threads[i]._queue, &msg);
SDL_WaitThread(threads[i]._thread, &status);
messageQueue_deinit(&threads[i]._queue);
}
}
}
av_freep(&_this->_pool.buffer);
objectPool_deinit(&_this->_pool);
}
//线程池，线程处理过程
int threadPool_threadProc(void* data)
{
ThreadInfo* info = (ThreadInfo*)data;
int msg = 1;
while (msg) {
info->_fn(info->_arg);
objectPool_restore(&info->_threadPool->_pool, info);
messageQueue_wait(&info->_queue, &msg);
}
return 0;
}
//在线程池中运行方法
void threadPool_run(ThreadPool* _this, SDL_ThreadFunction fn, void* arg) {
ThreadInfo* info = (ThreadInfo*)objectPool_take(&_this->_pool, -1);
info->_fn = fn;
info->_arg = arg;
if (info->_thread)
{
int msg = 1;
messageQueue_push(&info->_queue, &msg);
}
else
{
info->_threadPool = _this;
messageQueue_init(&info->_queue, 1, sizeof(int));
info->_thread = SDL_CreateThread(threadPool_threadProc, "threadPool_threadProc", info);
}
}
//在播放线程中运行方法
void play_beginInvoke(Play* _this, SDL_ThreadFunction fn, void* arg)
{
PlayMessage msg;
msg.type = PLAYMESSAGETYPE_INVOKE;
msg.param1 = fn;
msg.param2 = arg;
messageQueue_push(&_this->mq, &msg);
}
//#include<chrono>
/// <summary>
/// 返回当前时间
/// </summary>
/// <returns>当前时间，单位秒，精度微秒</returns>
static double getCurrentTime()
{
//此处用的是ffmpeg的av_gettime_relative。如果没有ffmpeg环境，则可替换成平台获取时钟的方法：单位为秒，精度需要微妙，相对绝对时钟都可以。
return av_gettime_relative() / 1000000.0;
//return std::chrono::time_point_cast <std::chrono::nanoseconds>(std::chrono::high_resolution_clock::now()).time_since_epoch().count() / 1e+9;
}
/// <summary>
/// 重置时钟同步
/// 通常用于暂停、定位
/// </summary>
/// <param name="syn">时钟同步对象</param>
void synchronize_reset(Synchronize* syn) {
SynchronizeType type = syn->type;
memset(syn, 0, sizeof(Synchronize));
syn->type = type;
}
/// <summary>
/// 获取主时钟
/// </summary>
/// <param name="syn">时钟同步对象</param>
/// <returns>主时钟对象</returns>
Clock* synchronize_getMasterClock(Synchronize* syn) {
switch (syn->type)
{
case SYNCHRONIZETYPE_AUDIO:
return &syn->audio;
case SYNCHRONIZETYPE_VIDEO:
return &syn->video;
case SYNCHRONIZETYPE_ABSOLUTE:
return &syn->absolute;
default:
break;
}
return 0;
}
/// <summary>
/// 获取主时钟的时间
/// </summary>
/// <param name="syn">时钟同步对象</param>
/// <returns>时间，单位s</returns>
double synchronize_getMasterTime(Synchronize* syn) {
return getCurrentTime() - synchronize_getMasterClock(syn)->startTime;
}
/// <summary>
/// 设置时钟的时间
/// </summary>
/// <param name="syn">时钟同步对象</param>
/// <param name="pts">当前时间，单位s</param>
void synchronize_setClockTime(Synchronize* syn, Clock* clock, double pts)
{
clock->currentPts = pts;
clock->startTime = getCurrentTime() - pts;
}
/// <summary>
/// 获取时钟的时间
/// </summary>
/// <param name="syn">时钟同步对象</param>
/// <param name="clock">时钟对象</param>
/// <returns>时间，单位s</returns>
double synchronize_getClockTime(Synchronize* syn, Clock* clock)
{
return getCurrentTime() - clock->startTime;
}
/// <summary>
/// 更新视频时钟
/// </summary>
/// <param name="syn">时钟同步对象</param>
/// <param name="pts">视频帧pts,单位为s</param>
/// <param name="duration">视频帧时长,单位为s。缺省值为0，内部自动估算duration</param>
/// <returns>大于0则延时值为延时时长，等于0显示，小于0丢帧</returns>
double synchronize_updateVideo(Synchronize* syn, double pts, double duration)
{
if (duration == 0)
//估算duration
{
if (pts != syn->video.currentPts)
syn->estimateVideoDuration = (syn->estimateVideoDuration * syn->n + pts - syn->video.currentPts) / (double)(syn->n + 1);
duration = syn->estimateVideoDuration;
//只估算最新3帧
if (syn->n++ > 3)
syn->estimateVideoDuration = syn->n = 0;
if (duration == 0)
duration = 0.1;
}
if (syn->video.startTime == 0)
{
syn->video.startTime = getCurrentTime() - pts;
}
//以下变量时间单位为s
//当前时间
double currentTime = getCurrentTime() - syn->video.startTime;
//计算时间差,大于0则late，小于0则early。
double diff = currentTime - pts;
double sDiff = 0;
if (syn->type != SYNCHRONIZETYPE_VIDEO && synchronize_getMasterClock(syn)->startTime != 0)
//同步到主时钟
{
sDiff = syn->video.startTime - synchronize_getMasterClock(syn)->startTime;
diff += sDiff;
}
修正时间，时钟和视频帧偏差超过0.1s时重新设置起点时间。
//if (diff > 0.1)
//{
// syn->video.startTime = getCurrentTime() - pts;
// currentTime = pts;
// diff = 0;
//}
//时间早了延时
if (diff < -0.001)
{
if (diff < -0.1)
{
diff = -0.1;
}
//printf("video-time：%.3lfs audio-time:%.3lfs avDiff:%.4lfms early:%.4lfms \n", getCurrentTime() - syn->video.startTime, getCurrentTime() - syn->audio.startTime, sDiff * 1000, diff * 1000);
return -diff;
}
syn->video.currentPts = pts;
//时间晚了丢帧，duration为一帧的持续时间，在一个duration内是正常时间，加一个duration作为阈值来判断丢帧。
if (diff > 2 * duration)
{
//printf("time:%.3lfs avDiff %.4lfms late for:%.4lfms droped\n", pts, sDiff * 1000, diff * 1000);
return -1;
}
//更新视频时钟
printf("video-time：%.3lfs audio-time:%.3lfs absolute-time:%.3lfs synDiff:%.4lfms diff:%.4lfms \r", pts, getCurrentTime() - syn->audio.startTime, getCurrentTime() - syn->absolute.startTime, sDiff * 1000, diff * 1000);
syn->video.startTime = getCurrentTime() - pts;
if (syn->absolute.startTime == 0)
{
syn->absolute.startTime = syn->video.startTime;
}
return 0;
}
//double lastTime = 0;
/// <summary>
/// 更新音频时钟
/// </summary>
/// <param name="syn">时钟同步对象</param>
/// <param name="samples">采样数</param>
/// <param name="samplerate">采样率</param>
/// <returns>应该播放的采样数</returns>
int synchronize_updateAudio(Synchronize* syn, int samples, int samplerate) {
if (syn->type != SYNCHRONIZETYPE_AUDIO && synchronize_getMasterClock(syn)->startTime != 0)
{
//同步到主时钟
double audioTime = getCurrentTime() - syn->audio.startTime;
double diff = 0;
diff = synchronize_getMasterTime(syn) - audioTime;
int oldSamples = samples;
if (fabs(diff) > 0.01) {
samples += diff * samplerate;
}
if (samples < 0)
{
samples = 0;
}
if (samples > oldSamples * 2)
{
samples = oldSamples * 2;
}
}
syn->audio.currentPts += (double)samples / samplerate;
syn->audio.startTime = getCurrentTime() - syn->audio.currentPts;
if (syn->absolute.startTime == 0)
{
syn->absolute.startTime = syn->audio.startTime;
}
return samples;
}
/// <summary>
/// 更新音频时钟，通过数据长度
/// </summary>
/// <param name="syn">时钟同步对象</param>
/// <param name="bytesSize">数据长度</param>
/// <param name="samplerate">采样率</param>
/// <param name="channels">声道数</param>
/// <param name="bitsPerSample">位深</param>
/// <returns>应该播放的数据长度</returns>
int synchronize_updateAudioByBytesSize(Synchronize* syn, size_t bytesSize, int samplerate, int channels, int bitsPerSample) {
return synchronize_updateAudio(syn, bytesSize / (channels * bitsPerSample / 8), samplerate) * (bitsPerSample / 8) * channels;
}
//初始化解码器
static int decoder_init(Play* play, Decoder* decoder, int wantFifoPacketSize, int wantFifoFrameSize) {
//创建解码上下文
decoder->codecContext = avcodec_alloc_context3(NULL);
AVDictionary* opts = NULL;
if (decoder->codecContext == NULL)
{
LOG_ERROR("Could not allocate AVCodecContext");
return ERRORCODE_DECODER_CANNOTALLOCATECONTEXT;
}
//获取解码器
if (avcodec_parameters_to_context(decoder->codecContext, play->formatContext->streams[decoder->streamIndex]->codecpar) < 0)
{
LOG_ERROR("Could not init AVCodecContext");
return ERRORCODE_DECODER_SETPARAMFAILED;
}
AVCodec* codec = avcodec_find_decoder(decoder->codecContext->codec_id);
if (codec == NULL) {
LOG_ERROR("Codec not found");
return ERRORCODE_DECODER_CANNOTFINDDECODER;
}
//使用多线程解码
if (!av_dict_get(opts, "threads", NULL, 0))
av_dict_set(&opts, "threads", "auto", 0);
//打开解码器
if (avcodec_open2(decoder->codecContext, codec, &opts) < 0) {
LOG_ERROR("Could not open codec");
av_dict_free(&opts);
return ERRORCODE_DECODER_OPENFAILED;
}
av_dict_free(&opts);
//初始化临时帧
decoder->frame = av_frame_alloc();
if (!decoder->frame)
{
LOG_ERROR("Alloc avframe failed");
return ERRORCODE_FRAME_ALLOCFAILED;
}
//初始化包队列
decoder->fifoPacket = av_fifo_alloc(sizeof(AVPacket*) * wantFifoPacketSize);
if (!decoder->fifoPacket)
{
LOG_ERROR("alloc packet fifo failed");
return ERRORCODE_FIFO_ALLOCFAILED;
}
//初始化帧队列
decoder->fifoFrame = av_fifo_alloc(sizeof(AVFrame*) * wantFifoFrameSize);
if (!decoder->fifoFrame)
{
LOG_ERROR("alloc frame fifo failed");
return ERRORCODE_FIFO_ALLOCFAILED;
}
return 0;
}
//清空解码队列
static void decoder_clear(Play* play, Decoder* decoder) {
//清空包队列
if (decoder->fifoPacket)
{
while (av_fifo_size(decoder->fifoPacket) > 0)
{
AVPacket* packet;
av_fifo_generic_read(decoder->fifoPacket, &packet, sizeof(AVPacket*), NULL);
if (packet != &play->packet)
{
av_packet_unref(packet);
av_packet_free(&packet);
}
}
}
//清空帧队列
if (decoder->fifoFrame)
{
while (av_fifo_size(decoder->fifoFrame) > 0)
{
AVFrame* frame;
av_fifo_generic_read(decoder->fifoFrame, &frame, sizeof(AVFrame*), NULL);
av_frame_unref(frame);
av_frame_free(&frame);
}
}
//清空解码器缓存
if (decoder->codecContext)
{
avcodec_flush_buffers(decoder->codecContext);
}
}
//反初始化解码器
static void decoder_deinit(Play* play, Decoder* decoder)
{
decoder_clear(play, decoder);
if (decoder->codecContext)
{
avcodec_close(decoder->codecContext);
avcodec_free_context(&decoder->codecContext);
}
if (decoder->fifoPacket)
{
av_fifo_free(decoder->fifoPacket);
decoder->fifoPacket = NULL;
}
if (decoder->fifoFrame)
{
av_fifo_free(decoder->fifoFrame);
decoder->fifoFrame = NULL;
}
if (decoder->frame)
{
if (decoder->frame->format != -1)
{
av_frame_unref(decoder->frame);
}
av_frame_free(&decoder->frame);
}
decoder->eofFrame = 0;
}
//解码
static int decoder_decode(Play* play, Decoder* decoder) {
int ret = 0;
AVPacket* packet = NULL;
if (decoder->streamIndex == -1)
{
LOG_ERROR("Decoder missing a stream");
return ERRORCODE_DECODER_MISSINGASTREAMTODECODE;
}
if (av_fifo_space(decoder->fifoFrame) < 1)
//帧队列已满
{
goto end;
}
//接收上次解码的帧
while (avcodec_receive_frame(decoder->codecContext, decoder->frame) == 0) {
AVFrame* frame = av_frame_clone(decoder->frame);
av_frame_unref(decoder->frame);
av_fifo_generic_write(decoder->fifoFrame, &frame, sizeof(AVFrame*), NULL);
if (av_fifo_space(decoder->fifoFrame) < 1)
//帧队列已满
{
goto end;
}
}
if (av_fifo_size(decoder->fifoPacket) > 0)
//包队列有数据，开始解码
{
av_fifo_generic_read(decoder->fifoPacket, &packet, sizeof(AVPacket*), NULL);
//发送包
if (avcodec_send_packet(decoder->codecContext, packet) < 0)
{
LOG_ERROR("Decode error");
ret = ERRORCODE_DECODER_SENDPACKEDFAILED;
goto end;
}
//接收解码的帧
while (avcodec_receive_frame(decoder->codecContext, decoder->frame) == 0) {
AVFrame* frame = av_frame_clone(decoder->frame);
av_frame_unref(decoder->frame);
av_fifo_generic_write(decoder->fifoFrame, &frame, sizeof(AVFrame*), NULL);
if (av_fifo_space(decoder->fifoFrame) < 1)
//帧队列已满
{
goto end;
}
}
}
if (play->eofPacket)
{
decoder->eofFrame = 1;
}
end:
if (packet && packet != &play->packet)
{
av_packet_unref(packet);
av_packet_free(&packet);
}
return ret;
}
//音频设备播放回调
static void audio_callback(void* userdata, uint8_t* stream, int len) {
Play* play = (Play*)userdata;
int samples = 0;
//读取队列中的音频数据，由于AVAudioFifo非线程安全，且是子线程触发此回调，所以需要加锁
SDL_LockMutex(play->audio.mutex);
if (!play->isPaused)
{
if (av_audio_fifo_size(play->audio.playFifo) >= play->audio.spec.samples)
{
int drain = 0;
//需要写入的数据量
samples = play->audio.spec.samples;
//时钟同步，获取应该写入的数据量，如果是同步到音频，则需要写入的数据量始终等于应该写入的数据量。
samples = synchronize_updateAudio(&play->synchronize, samples, play->audio.spec.freq);
samples += play->audio.accumulateSamples;
if (samples > av_audio_fifo_size(play->audio.playFifo))
{
play->audio.accumulateSamples = samples - av_audio_fifo_size(play->audio.playFifo);
samples = av_audio_fifo_size(play->audio.playFifo);
}
else
{
play->audio.accumulateSamples = 0;
}
if (samples > play->audio.spec.samples)
//比需要写入的数据量大，则丢弃一部分
{
drain = samples - play->audio.spec.samples;
samples = play->audio.spec.samples;
}
if (play->audio.volume + SDL_MIX_MAXVOLUME != SDL_MIX_MAXVOLUME)
//改变音量
{
if (!play->audio.mixBuffer)
{
play->audio.mixBuffer = (uint8_t*)av_malloc(len);
if (!play->audio.mixBuffer)
{
LOG_ERROR("mixBuffer alloc failed");
return;
}
}
av_audio_fifo_read(play->audio.playFifo, (void**)&play->audio.mixBuffer, samples);
int len2 = av_samples_get_buffer_size(0, play->audio.spec.channels, samples, play->audio.forceSampleFormat, 1);
memset(stream, 0, len2);
SDL_MixAudioFormat(stream, play->audio.mixBuffer, play->audio.spec.format, len2, play->audio.volume + SDL_MIX_MAXVOLUME);
}
else
//直接写入
{
av_audio_fifo_read(play->audio.playFifo, (void**)&stream, samples);
}
av_audio_fifo_drain(play->audio.playFifo, drain);
}
}
SDL_UnlockMutex(play->audio.mutex);
//补充静音数据
int fillSize = av_samples_get_buffer_size(0, play->audio.spec.channels, samples, play->audio.forceSampleFormat, 1);
if (fillSize < 0)
fillSize = 0;
if (len - fillSize > 0)
{
memset(stream + fillSize, 0, len - fillSize);
}
}
//初始化音频模块
static int audio_init(Play* play, Audio* audio) {
//初始化解码器
if (decoder_init(play, &audio->decoder, 600, 100) != 0)
{
LOG_ERROR("audio decoder init error");
return ERRORCODE_AUDIO_DECODERINITFAILED;
}
//初始化sdl
if ((SDL_WasInit(0) & (SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) == 0)
{
if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
LOG_ERROR("Could not initialize SDL - %s", SDL_GetError());
return ERRORCODE_SDL_INITFAILED;
}
}
//打开音频设备
audio->wantedSpec.channels = av_get_channel_layout_nb_channels(audio->decoder.codecContext->channel_layout);
audio->wantedSpec.freq = audio->decoder.codecContext->sample_rate;
audio->wantedSpec.format = AUDIO_F32SYS;
audio->wantedSpec.silence = 0;
audio->wantedSpec.samples = FFMAX(512, 2 << av_log2(audio->wantedSpec.freq / 30));
audio->wantedSpec.callback = audio_callback;
audio->wantedSpec.userdata = play;
audio->audioId = SDL_OpenAudioDevice(NULL, 0, &audio->wantedSpec, &audio->spec, SDL_AUDIO_ALLOW_ANY_CHANGE);
if (audio->audioId < 2)
{
LOG_ERROR("Open audio device error");
return ERRORCODE_SDL_CANNOTOPENDEVICE;
}
//匹配音频格式
switch (audio->spec.format)
{
case AUDIO_S16SYS:
audio->forceSampleFormat = AV_SAMPLE_FMT_S16;
break;
case AUDIO_S32SYS:
audio->forceSampleFormat = AV_SAMPLE_FMT_S32;
break;
case AUDIO_F32SYS:
audio->forceSampleFormat = AV_SAMPLE_FMT_FLT;
break;
default:
LOG_ERROR("audio device format was not surported %d", (int)audio->spec.format);
return ERRORCODE_AUDIO_UNSUPORTDEVICESAMPLEFORMAT;
}
//初始化音频帧队列的互斥锁
audio->mutex = SDL_CreateMutex();
if (!audio->mutex)
{
LOG_ERROR("alloc mutex failed");
return ERRORCODE_SDL_CANNOTCREATEMUTEX;
}
//音频播放队列
audio->playFifo = av_audio_fifo_alloc(audio->forceSampleFormat, audio->spec.channels, audio->spec.samples * 30);
if (!audio->playFifo)
{
LOG_ERROR("alloc audio fifo failed");
return ERRORCODE_FIFO_ALLOCFAILED;
}
//设备开启播放
SDL_PauseAudioDevice(audio->audioId, 0);
return 0;
}
//音频初始化
static void audio_deinit(Play* play, Audio* audio)
{
if (audio->audioId >= 2)
{
SDL_PauseAudioDevice(audio->audioId, 1);
SDL_CloseAudioDevice(audio->audioId);
audio->audioId = 0;
}
if (audio->mutex)
{
SDL_DestroyMutex(audio->mutex);
audio->mutex = NULL;
}
if (play->audio.playFifo)
{
av_audio_fifo_free(play->audio.playFifo);
play->audio.playFifo = NULL;
}
if (audio->swrContext)
{
swr_free(&audio->swrContext);
}
if (audio->swrBuffer)
{
av_freep(&audio->swrBuffer);
}
if (audio->mixBuffer)
{
av_freep(&audio->mixBuffer);
}
decoder_deinit(play, &audio->decoder);
audio->eofPlay = 0;
audio->sofPlay = 0;
}
//音频播放
static int audio_play(Play* play, Audio* audio) {
if (audio->decoder.streamIndex == -1)
{
LOG_ERROR("audio play missing audio stream");
//没有音频流
return ERRORCODE_AUDIO_MISSINGSTREAM;
}
if (play->video.decoder.streamIndex != -1 && !play->video.sofDisplay)
{
return 0;
}
while (av_fifo_size(play->audio.decoder.fifoFrame) > 0)
{
AVFrame* frame = NULL;
uint8_t* data = NULL;
int dataSize = 0;
int samples = 0;
av_fifo_generic_peek(play->audio.decoder.fifoFrame, &frame, sizeof(AVFrame*), NULL);
if (play->audio.forceSampleFormat != play->audio.decoder.codecContext->sample_fmt || play->audio.spec.freq != frame->sample_rate || play->audio.spec.channels != frame->channels)
//重采样
{
//计算输入采样数
int out_count = (int64_t)frame->nb_samples * play->audio.spec.freq / frame->sample_rate + 256;
//计算输出数据大小
int out_size = av_samples_get_buffer_size(NULL, play->audio.spec.channels, out_count, play->audio.forceSampleFormat, 0);
//输入数据指针
const uint8_t** in = (const uint8_t**)frame->extended_data;
//输出缓冲区指针
uint8_t** out = &play->audio.swrBuffer;
int len2 = 0;
if (out_size < 0) {
LOG_ERROR("sample output size value %d was invalid", out_size);
return ERRORCODE_AUDIO_SAMPLESSIZEINVALID;
}
if (!play->audio.swrContext)
//初始化重采样对象
{
play->audio.swrContext = swr_alloc_set_opts(NULL, av_get_default_channel_layout(play->audio.spec.channels), play->audio.forceSampleFormat, play->audio.spec.freq, play->audio.decoder.codecContext->channel_layout, play->audio.decoder.codecContext->sample_fmt, play->audio.decoder.codecContext->sample_rate, 0, NULL);
if (!play->audio.swrContext || swr_init(play->audio.swrContext) < 0) {
LOG_ERROR("swr_alloc_set_opts or swr_init failed");
return ERRORCODE_AUDIO_SWRINITFAILED;
}
}
if (!play->audio.swrBuffer)
//申请输出缓冲区
{
play->audio.swrBuffer = (uint8_t*)av_mallocz(out_size);
if (!play->audio.swrBuffer)
{
LOG_ERROR("audio swr ouput buffer alloc failed");
return ERRORCODE_MEMORY_ALLOCFAILED;
}
}
//执行重采样
len2 = swr_convert(play->audio.swrContext, out, out_count, in, frame->nb_samples);
if (len2 < 0) {
LOG_ERROR("swr_convert failed");
return ERRORCODE_AUDIO_CANNOTCONVERSAMPLE;
}
//取得输出数据
data = play->audio.swrBuffer;
//输出数据长度
dataSize = av_samples_get_buffer_size(0, play->audio.spec.channels, len2, play->audio.forceSampleFormat, 1);
samples = len2;
}
else
//无需重采样
{
data = frame->data[0];
dataSize = av_samples_get_buffer_size(frame->linesize, frame->channels, frame->nb_samples, play->audio.forceSampleFormat, 0);
samples = frame->nb_samples;
}
if (dataSize < 0)
{
LOG_ERROR("sample data size value %d was invalid", dataSize);
return ERRORCODE_AUDIO_SAMPLESSIZEINVALID;
}
//写入播放队列
SDL_LockMutex(play->audio.mutex);
if (av_audio_fifo_space(play->audio.playFifo) >= samples)
{
//同步(修正)时钟
AVRational timebase = play->formatContext->streams[audio->decoder.streamIndex]->time_base;
//当前帧的时间戳
double pts = (double)frame->pts * timebase.num / timebase.den;
//减去播放队列剩余数据的时长就是当前的音频时钟
pts -= (double)av_audio_fifo_size(play->audio.playFifo) / play->audio.spec.freq;
//设置音频时钟
synchronize_setClockTime(&play->synchronize, &play->synchronize.audio, pts);
//同步(修正)时钟--end
//写入播放队列
av_audio_fifo_write(play->audio.playFifo, (void**)&data, samples);
//解码队列的帧出队
av_fifo_generic_read(play->audio.decoder.fifoFrame, &frame, sizeof(AVFrame*), NULL);
av_frame_unref(frame);
av_frame_free(&frame);
if (!audio->sofPlay)
//标记开始
{
audio->sofPlay = 1;
}
}
else
{
SDL_UnlockMutex(play->audio.mutex);
break;
}
SDL_UnlockMutex(play->audio.mutex);
}
//计算睡眠延时
SDL_LockMutex(play->audio.mutex);
double canSleepTime = (double)av_audio_fifo_size(play->audio.playFifo) / play->audio.spec.freq;
double wakeupTime = getCurrentTime() + canSleepTime;
if (play->video.decoder.streamIndex == -1 || wakeupTime < play->wakeupTime)
{
play->wakeupTime = wakeupTime;
}
SDL_UnlockMutex(play->audio.mutex);
if (av_fifo_size(play->audio.decoder.fifoFrame) < 1 && audio->decoder.eofFrame)
//标记结束
{
audio->eofPlay = 1;
}
return 0;
}
//初始化视频模块
static int video_init(Play* play, Video* video) {
//初始化解码器
if (decoder_init(play, &video->decoder, 600, 1) != 0)
{
LOG_ERROR("video decoder init error");
return ERRORCODE_VIDEO_DECODERINITFAILED;
}
//初始化sdl
if ((SDL_WasInit(0) & (SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) == 0)
{
if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
LOG_ERROR("Could not initialize SDL - %s", SDL_GetError());
return ERRORCODE_SDL_INITFAILED;
}
}
return 0;
}
//反初始化视频模块
static void video_deinit(Play* play, Video* video) {
if (video->swsContext)
{
sws_freeContext(video->swsContext);
video->swsContext = NULL;
}
if (video->swsBuffer)
{
av_free(video->swsBuffer);
video->swsBuffer = NULL;
}
if (video->sdlTexture)
{
SDL_DestroyTexture(video->sdlTexture);
video->sdlTexture = NULL;
}
if (video->sdlRenderer)
{
SDL_DestroyRenderer(video->sdlRenderer);
video->sdlRenderer = NULL;
}
if (video->screen)
{
SDL_DestroyWindow(video->screen);
video->screen = NULL;
}
decoder_deinit(play, &video->decoder);
video->eofDisplay = 0;
video->sofDisplay = 0;
}
double get_rotation(AVStream* st)
{
AVDictionaryEntry* rotate_tag = av_dict_get(st->metadata, "rotate", NULL, 0);
double theta = 0;
if (rotate_tag && *rotate_tag->value && strcmp(rotate_tag->value, "0")) {
theta = atof(rotate_tag->value);
}
theta -= 360 * floor(theta / 360 + 0.9 / 360);
if (fabs(theta - 90 * round(theta / 90)) > 2)
{
LOG_INFO("Odd rotation angle");
}
return theta;
}
/// <summary>
/// 计算旋转的矩形大小
/// </summary>
/// <param name="src">原图像区域</param>
/// <param name="dst">目标区域</param>
/// <param name="angle">旋转角度</param>
/// <returns></returns>
static SDL_Rect getRotateRect(SDL_Rect *srcRect, SDL_Rect* dstRect,double angle) {
SDL_Rect targetRect;
const double PI = 3.1415926535897935384626;
double theta = PI / 180.0 * angle;
//计算旋转后的边框大小
int width = srcRect->h * fabs(sin(theta) )+ srcRect->w * fabs(cos(theta)) + 0.5;
int height = srcRect->h * fabs(cos(theta)) + srcRect->w * fabs(sin(theta)) + 0.5;
double srcRatio = (double)srcRect->w / srcRect->h;
double srcBorderRatio = (double)width / height;
double dstRatio = (double)dstRect->w / dstRect->h;
//计算边框缩放到目标区域的大小
int zoomWidth;
int zoomHeight;
if (srcBorderRatio > dstRatio)
{
zoomWidth = dstRect->w;
zoomHeight = dstRect->w / srcBorderRatio;
}
else
{
zoomWidth = dstRect->h * srcBorderRatio;
zoomHeight = dstRect->h;
}
//通过缩放后的边框计算还原的图像大小
targetRect.h = (double)zoomWidth / (fabs(sin(theta) )+ srcRatio * fabs(cos(theta)));
targetRect.w = targetRect.h * srcRatio;
targetRect.x = (dstRect->w- targetRect.w ) / 2;
targetRect.y = (dstRect->h- targetRect.h ) / 2;
return targetRect;
}
//渲染到窗口
static int video_present(Play* play, Video* video, AVFrame* frame)
{
SDL_Rect sdlRect;
SDL_Rect sdlRect2;
uint8_t* dst_data[4];
int dst_linesize[4];
if (!video->screen)
{
//创建窗口
video->screen = SDL_CreateWindow("video play window", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
video->screen_w, video->screen_h,
SDL_WINDOW_OPENGL);
if (!video->screen) {
LOG_ERROR("SDL: could not create window - exiting:%s\n", SDL_GetError());
return ERRORCODE_SDL_CREATEWINDOWFAILED;
}
}
if (!video->sdlRenderer)
//初始化sdl纹理
{
video->angle = get_rotation(play->formatContext->streams[play->video.decoder.streamIndex]);
video->sdlRenderer = SDL_CreateRenderer(video->screen, -1, 0);
if (!video->sdlRenderer)
{
LOG_ERROR("Create sdl renderer error");
return ERRORCODE_SDL_CREATERENDERERFAILED;
}
//获取合适的像素格式
struct TextureFormatEntry format;
format.format = AV_PIX_FMT_YUV420P;
format.texture_fmt = SDL_PIXELFORMAT_IYUV;
for (int i = 0; i < sizeof(sdl_texture_format_map) / sizeof(struct TextureFormatEntry); i++)
{
if (sdl_texture_format_map[i].format == video->decoder.codecContext->pix_fmt)
{
format = sdl_texture_format_map[i];
break;
}
}
video->forcePixelFormat = format.format;
//创建和视频大小一样的纹理
video->sdlTexture = SDL_CreateTexture(video->sdlRenderer, format.texture_fmt, SDL_TEXTUREACCESS_STREAMING, video->decoder.codecContext->width, video->decoder.codecContext->height);
if (!video->sdlTexture)
{
LOG_ERROR("Create sdl texture error");
return ERRORCODE_SDL_CREATETEXTUREFAILED;
}
}
if (video->forcePixelFormat != video->decoder.codecContext->pix_fmt)
//重采样-格式转换
{
video->swsContext = sws_getCachedContext(video->swsContext, video->decoder.codecContext->width, video->decoder.codecContext->height, video->decoder.codecContext->pix_fmt, video->decoder.codecContext->width, video->decoder.codecContext->height, video->forcePixelFormat, SWS_FAST_BILINEAR, NULL, NULL, NULL);
if (!video->swsContext)
{
LOG_ERROR("sws_getCachedContext failed");
return ERRORCODE_VIDEO_CANNOTGETSWSCONTEX;
}
if (!video->swsBuffer)
{
video->swsBuffer = (uint8_t*)av_malloc(av_image_get_buffer_size(video->forcePixelFormat, video->decoder.codecContext->width, video->decoder.codecContext->height, 64));
if (video->swsBuffer)
{
LOG_ERROR("audio swr ouput buffer alloc failed");
return ERRORCODE_MEMORY_ALLOCFAILED;
}
}
if (av_image_fill_arrays(dst_data, dst_linesize, video->swsBuffer, video->forcePixelFormat, video->decoder.codecContext->width, video->decoder.codecContext->height, 1) < 0)
{
LOG_ERROR("sws_getCachedContext failed");
return ERRORCODE_VIDEO_IMAGEFILLARRAYFAILED;
}
if (sws_scale(video->swsContext, frame->data, frame->linesize, 0, frame->height, dst_data, dst_linesize) < 0)
{
LOG_ERROR("Call sws_scale error");
return ERRORCODE_VIDEO_CANNOTRESAMPLEAFRAME;
}
}
else
//无需重采样
{
memcpy(dst_data, frame->data, sizeof(uint8_t*) * 4);
memcpy(dst_linesize, frame->linesize, sizeof(int) * 4);
}
//窗口区域
sdlRect.x = 0;
sdlRect.y = 0;
sdlRect.w = video->screen_w;
sdlRect.h = video->screen_h;
//视频区域
sdlRect2.x = 0;
sdlRect2.y = 0;
sdlRect2.w = video->decoder.codecContext->width;
sdlRect2.h = video->decoder.codecContext->height;
//渲染到sdl窗口
SDL_RenderClear(video->sdlRenderer);
SDL_UpdateYUVTexture(video->sdlTexture, &sdlRect2, dst_data[0], dst_linesize[0], dst_data[1], dst_linesize[1], dst_data[2], dst_linesize[2]);
if (video->angle == 0)
SDL_RenderCopy(video->sdlRenderer, video->sdlTexture, NULL, &sdlRect);
else
//旋转视频
{
SDL_Rect sdlRect3;
sdlRect3= getRotateRect(&sdlRect2,&sdlRect,video->angle);
SDL_RenderCopyEx(video->sdlRenderer, video->sdlTexture, NULL
, &sdlRect3, video->angle, 0, SDL_FLIP_NONE);
}
SDL_RenderPresent(video->sdlRenderer);
}
//视频显示
static int video_display(Play* play, Video* video) {
if (play->video.decoder.streamIndex == -1)
//没有视频流
{
return ERRORCODE_VIDEO_MISSINGSTREAM;
}
if (play->audio.decoder.streamIndex != -1 && video->sofDisplay && !play->audio.sofPlay)
return 0;
AVFrame* frame = NULL;
if (av_fifo_size(video->decoder.fifoFrame) > 0)
{
av_fifo_generic_peek(video->decoder.fifoFrame, &frame, sizeof(AVFrame*), NULL);
//---------------时钟同步--------------
AVRational timebase = play->formatContext->streams[video->decoder.streamIndex]->time_base;
//计算视频帧的pts
double pts = frame->pts * (double)timebase.num / timebase.den;
//视频帧的持续时间
double duration = frame->pkt_duration * (double)timebase.num / timebase.den;
double delay = synchronize_updateVideo(&play->synchronize, pts, duration);
if (delay > 0)
//延时
{
play->wakeupTime = getCurrentTime() + delay;
return 0;
}
else if (delay < 0)
//丢帧
{
av_fifo_generic_read(video->decoder.fifoFrame, &frame, sizeof(AVFrame*), NULL);
av_frame_unref(frame);
av_frame_free(&frame);
return 0;
}
else
//播放
{
av_fifo_generic_read(video->decoder.fifoFrame, &frame, sizeof(AVFrame*), NULL);
}
//---------------时钟同步-------------- end
}
else if (video->decoder.eofFrame)
{
video->sofDisplay = 1;
//标记结束
video->eofDisplay = 1;
}
if (frame)
{
//渲染
video_present(play, video, frame);
av_frame_unref(frame);
av_frame_free(&frame);
if (!video->sofDisplay)
video->sofDisplay = 1;
if (play->step)
{
play->step--;
}
}
return 0;
}
static int interrupt_cb(void* arg) {
Play* play = (Play*)arg;
return play->exitFlag;
}
//打开输入流
static int packet_open(Play* play) {
//打开输入流
play->formatContext = avformat_alloc_context();
play->formatContext->interrupt_callback.callback = interrupt_cb;
play->formatContext->interrupt_callback.opaque = play;
if (avformat_open_input(&play->formatContext, play->url, NULL, NULL) != 0) {
LOG_ERROR("Couldn't open input stream");
return ERRORCODE_PACKET_CANNOTOPENINPUTSTREAM;
}
//查找输入流信息
if (avformat_find_stream_info(play->formatContext, NULL) < 0) {
LOG_ERROR("Couldn't find stream information");
return ERRORCODE_PACKET_CANNOTFINDSTREAMINFO;
}
//ignore = 0;
play->video.decoder.streamIndex = -1;
//获取视频流
for (unsigned i = 0; i < play->formatContext->nb_streams; i++)
if (play->formatContext->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
play->video.decoder.streamIndex = i;
break;
}
play->audio.decoder.streamIndex = -1;
//获取音频流
for (unsigned i = 0; i < play->formatContext->nb_streams; i++)
if (play->formatContext->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
play->audio.decoder.streamIndex = i;
break;
}
//没有找到任何流
if (play->video.decoder.streamIndex == -1 && play->audio.decoder.streamIndex == -1) {
LOG_ERROR("Didn't find any stream.");
return ERRORCODE_PACKET_DIDNOTFINDDANYSTREAM;
}
play->eofPacket = 0;
return 0;
}
//异步读取包完成后的操作
static int packet_readAwait(void* arg)
{
Play* play = (Play*)arg;
if (play->eofPacket == 0)
{
if (play->packet.stream_index == play->video.decoder.streamIndex)
//写入视频包队
{
AVPacket* packet = av_packet_clone(&play->packet);
av_fifo_generic_write(play->video.decoder.fifoPacket, &packet, sizeof(AVPacket*), NULL);
}
else if (play->packet.stream_index == play->audio.decoder.streamIndex)
//写入音频包队
{
AVPacket* packet = av_packet_clone(&play->packet);
av_fifo_generic_write(play->audio.decoder.fifoPacket, &packet, sizeof(AVPacket*), NULL);
}
av_packet_unref(&play->packet);
}
else if (play->eofPacket == AVERROR_EOF)
{
play->eofPacket = 1;
//写入空包flush解码器中的缓存
AVPacket* packet = &play->packet;
if (play->audio.decoder.fifoPacket)
av_fifo_generic_write(play->audio.decoder.fifoPacket, &packet, sizeof(AVPacket*), NULL);
if (play->video.decoder.fifoPacket)
av_fifo_generic_write(play->video.decoder.fifoPacket, &packet, sizeof(AVPacket*), NULL);
}
else
{
LOG_ERROR("read packet erro!\n");
play->exitFlag = 1;
play->isAsyncReading = 0;
return ERRORCODE_PACKET_READFRAMEFAILED;
}
play->isAsyncReading = 0;
return 0;
}
//异步读取包
static int packet_readAsync(void* arg)
{
Play* play = (Play*)arg;
play->eofPacket = av_read_frame(play->formatContext, &play->packet);
//回到播放线程处理包
play_beginInvoke(play, packet_readAwait, play);
return 0;
}
//读取包
static int packet_read(Play* play) {
if (play->isAsyncReading)
return 0;
if (play->eofPacket)
{
return 0;
}
if (play->video.decoder.streamIndex != -1 && av_fifo_space(play->video.decoder.fifoPacket) < 1)
//视频包队列已满
{
return 0;
}
if (play->audio.decoder.streamIndex != -1 && av_fifo_space(play->audio.decoder.fifoPacket) < 1)
//音频包队列已满
{
return 0;
}
if (!_pool)
//初始化线程池
{
_pool = (ThreadPool*)av_mallocz(sizeof(ThreadPool));
threadPool_init(_pool, 32);
}
play->isAsyncReading = 1;
//异步读取包
threadPool_run(_pool, packet_readAsync, play);
return 0;
}
static void play_eventHandler(Play* play);
//等待读包结束
static void packet_waitAsyncReadFinished(Play* play) {
//确保异步操作结束
while (play->isAsyncReading)
{
av_usleep(0.01 * 1000000);
play_eventHandler(play);
}
}
//关闭输入流
static void packet_close(Play* play) {
packet_waitAsyncReadFinished(play);
if (play->packet.data)
{
av_packet_unref(&play->packet);
}
if (play->formatContext)
{
avformat_close_input(&play->formatContext);
}
}
//定位
static int packet_seek(Play* play, double time) {
packet_waitAsyncReadFinished(play);
return avformat_seek_file(play->formatContext, -1, INT64_MIN, time * AV_TIME_BASE, INT64_MAX, 0) >= 0;
}
//设置窗口大小
void play_setWindowSize(Play* play, int width, int height) {
play->video.screen_w = width;
play->video.screen_h = height;
}
//定位
void play_seek(Play* play, double time) {
if (time < 0)
{
time = 0;
}
if (packet_seek(play, time))
{
//重置属性
play->audio.accumulateSamples = 0;
play->audio.sofPlay = 0;
play->video.sofDisplay = 0;
//清除缓存
decoder_clear(play, &play->video.decoder);
decoder_clear(play, &play->audio.decoder);
avformat_flush(play->formatContext);
if (play->audio.playFifo)
{
SDL_LockMutex(play->audio.mutex);
av_audio_fifo_reset(play->audio.playFifo);
synchronize_reset(&play->synchronize);
SDL_UnlockMutex(play->audio.mutex);
}
else
{
synchronize_reset(&play->synchronize);
}
//暂停时需要播放一帧
play->step = 1;
}
}
//暂停
void play_pause(Play* play, int isPaused) {
if (play->isPaused == isPaused)
return;
if (!isPaused)
{
play->audio.sofPlay = 0;
play->video.sofDisplay = 0;
synchronize_reset(&play->synchronize);
}
play->isPaused = isPaused;
}
//静音
void play_setVolume(Play* play, int value) {
//移动到0作为最大音量。则初始化memset后不需要设置默认音量。
if (value < 0)
value = 0;
value -= SDL_MIX_MAXVOLUME;
if (play->audio.volume == value)
return;
play->audio.volume = value;
}
int play_getVolume(Play* play) {
return play->audio.volume + SDL_MIX_MAXVOLUME;
}
//事件处理
static void play_eventHandler(Play* play) {
PlayMessage msg;
while (messageQueue_poll(&play->mq, &msg)) {
switch (msg.type)
{
case PLAYMESSAGETYPE_INVOKE:
SDL_ThreadFunction fn = (SDL_ThreadFunction)msg.param1;
fn(msg.param2);
break;
}
}
//处理窗口消息
SDL_Event sdl_event;
if (SDL_PollEvent(&sdl_event))
{
switch (sdl_event.type)
{
case SDL_WINDOWEVENT:
if (sdl_event.window.event == SDL_WINDOWEVENT_CLOSE)
play->exitFlag = 1;
break;
case SDL_KEYDOWN:
switch (sdl_event.key.keysym.sym) {
case SDLK_UP:
play_setVolume(play, play_getVolume(play) + 20);
break;
case SDLK_DOWN:
play_setVolume(play, play_getVolume(play) - 20);
break;
case SDLK_LEFT:
play_seek(play, synchronize_getMasterTime(&play->synchronize) - 10);
break;
case SDLK_RIGHT:
play_seek(play, synchronize_getMasterTime(&play->synchronize) + 10);
break;
case SDLK_SPACE:
play_pause(play, !play->isPaused);
break;
default:
break;
}
break;
}
}
}
//播放循环
static int play_loop(Play* play)
{
int ret = 0;
double remainingTime = 0;
while (!play->exitFlag)
{
if (!play->isPaused || play->step)
{
//解复用
if ((ret = packet_read(play)) != 0)
{
LOG_ERROR("read packet error");
ret = ERRORCODE_PLAY_READPACKETERROR;
break;
}
//视频解码
if ((ret = decoder_decode(play, &play->video.decoder)) != 0)
{
LOG_ERROR("video decode error");
ret = ERRORCODE_PLAY_VIDEODECODEERROR;
break;
}
//音频解码
if ((ret = decoder_decode(play, &play->audio.decoder)) != 0)
{
LOG_ERROR("audio decode error");
ret = ERRORCODE_PLAY_AUDIODECODEERROR;
break;
}
//延时等待
remainingTime = (play->wakeupTime - getCurrentTime()) / 2;
if (remainingTime > 0)
{
av_usleep(remainingTime * 1000000);
}
//视频显示
if ((ret = video_display(play, &play->video)) != 0)
{
LOG_ERROR("video display error");
ret = ERRORCODE_PLAY_VIDEODISPLAYERROR;
break;
}
//音频播放
if ((ret = audio_play(play, &play->audio)) != 0)
{
LOG_ERROR("audio play error");
ret = ERRORCODE_PLAY_AUDIOPLAYERROR;
break;
}
//检查结尾
if ((play->video.decoder.streamIndex == -1 || play->video.eofDisplay) && (play->audio.decoder.streamIndex == -1 || play->audio.eofPlay))
{
if (!play->isLoop)
break;
//循环播放，定位到起点
play->eofPacket = 0;
play->audio.decoder.eofFrame = 0;
play->video.decoder.eofFrame = 0;
play->audio.eofPlay = 0;
play->video.eofDisplay = 0;
play_seek(play, 0);
continue;
}
}
else
{
av_usleep(0.01 * 1000000);
}
//处理消息
play_eventHandler(play);
}
return ret;
}
/// <summary>
/// 播放
/// 单线程阻塞播放
/// </summary>
/// <param name="play">播放器对象</param>
/// <param name="url">输入流的地址，可以是本地路径、http、https、rtmp、rtsp等</param>
/// <returns>错误码，0表示无错误</returns>
int play_exec(Play* play, const char* url) {
int ret = 0;
play->url = (char*)url;
//打开输入流
if ((ret = packet_open(play)) != 0)
{
LOG_ERROR("open input error");
ret = ERRORCODE_PLAY_OPENINPUTSTREAMFAILED;
goto end;
}
//初始化视频模块
if (play->video.decoder.streamIndex != -1)
{
if ((ret = video_init(play, &play->video)) != 0)
{
LOG_ERROR("init video error");
ret = ERRORCODE_PLAY_VIDEOINITFAILED;
goto end;
}
}
//初始化音频模块
if (play->audio.decoder.streamIndex != -1)
{
if ((ret = audio_init(play, &play->audio)) != 0)
{
LOG_ERROR("init audio error");
ret = ERRORCODE_PLAY_AUDIOINITFAILED;
goto end;
}
}
else
{
play->synchronize.type = SYNCHRONIZETYPE_ABSOLUTE;
}
//初始化消息队列
if ((ret = messageQueue_init(&play->mq, 500, sizeof(PlayMessage))) != 0)
{
LOG_ERROR("open input error");
ret = ERRORCODE_PLAY_OPENINPUTSTREAMFAILED;
goto end;
}
//进入播放循环进行：解码-渲染-播放
if ((ret = play_loop(play)) != 0)
{
ret = ERRORCODE_PLAY_LOOPERROR;
}
end:
//销毁资源
if (play->video.decoder.streamIndex != -1)
{
video_deinit(play, &play->video);
}
if (play->audio.decoder.streamIndex != -1)
{
audio_deinit(play, &play->audio);
}
packet_close(play);
synchronize_reset(&play->synchronize);
messageQueue_deinit(&play->mq);
play->url = NULL;
play->exitFlag = 0;
return ret;
}
/// <summary>
/// 退出播放
/// </summary>
/// <param name="play">播放器对象</param>
void play_exit(Play* play)
{
play->exitFlag = 1;
}
#undef main
int main(int argc, char** argv) {
Play play;
//memset相当于初始化
memset(&play, 0, sizeof(Play));
play_setWindowSize(&play, 640, 360);
play.isLoop = 1;
//单线程阻塞播放
return play_exec(&play, "D:\\test.mp4");
}
完整代码项目：vs2022、makefile，Windows、Linux都可以运行，Linux需要自行配置ffmpeg和sdl
四、使用示例
#undef main
int main(int argc, char** argv) {
Play play;
//memset相当于初始化
memset(&play, 0, sizeof(Play));
play_setWindowSize(&play, 640, 360);
play.isLoop = 1;
//单线程阻塞播放。左快退、右快进、上下调音量、空格暂停。
return play_exec(&play, "D:\\test.mp4");
}
总结
以上就是今天要讲的内容，本文的播放器验证了单线程播放是可行的，尤其是播放本地文件可以做到完全单线程，那这样对于实现视频剪辑工具就有很大的帮助了，每多一条轨道只需要增加一个线程。而且采用异步读包之后也能正常播放网络流，2个线程播放视频依然比ffplay要优化。
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